<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
<html>
 <head>
  <meta http-equiv="content-type" content="text/html; charset=UTF-8">
  <title>Two-table examples</title>

 </head>
 <body><div class="manualnavbar" style="text-align: center;">
 <div class="prev" style="text-align: left; float: left;"><a href="sdodasrel.examples.one-table.html">One-table examples</a></div>
 <div class="next" style="text-align: right; float: right;"><a href="sdodasrel.examples.three-table.html">Three-table example</a></div>
 <div class="up"><a href="sdodasrel.examples.html">范例</a></div>
 <div class="home"><a href="index.html">PHP Manual</a></div>
</div><hr /><div id="sdodasrel.examples.two-table" class="section">
  <h2 class="title">Two-table examples</h2>
  <p class="para">
   The following set of examples all use two tables from the company 
   database: the company and department tables. These examples exercise 
   more of the function of the Relational DAS.
  </p>
  <p class="para">
   In this series of examples a company and department are created, 
   retrieved, updated, and finally deleted. This illustrates the 
   lifecycle for a data graph containing more than one object. Note that 
   this example clears out the company and department tables at the start 
   so that the exact results of the queries can be known.
  </p>
  <p class="para">
   You can find these examples combined into one script called
   <var class="filename">1cd-CRUD</var>
   in the
   <var class="filename">Scenarios</var>
   directory in the Relational DAS package.
  </p>

  <p class="para">
   <div class="example" id="example-5352">
    <p><strong>Example #1 One company, one department - Create</strong></p>
    <div class="example-contents"><p>
     As in the earlier example of creating just one company data object, 
     the first action after constructing the Relational DAS is to call
     <span class="function"><strong>createRootDataObject()</strong></span>
     to obtain the special root object of the otherwise empty data graph.
     The company object is then created as a child of the root object, 
     and the department object as a child of the company object.
    </p></div>
    <div class="example-contents"><p>
     When it comes to applying the changes, the Relational DAS has to 
     perform special processing to maintain the foreign keys that support 
     the containment relationships, especially if auto-generated primary 
     keys are involved. In this example, the relationship between the 
     auto-generated primary key 
     <var class="varname"><var class="varname">id</var></var>
     in the company table and the
     <var class="varname"><var class="varname">co_id</var></var>
     column in the department table must be maintained. When inserting a 
     company and department for the first time the Relational DAS has to 
     first insert the company row, then call PDO&#039;s
     <span class="function"><strong>getLastInsertId()</strong></span>
     method to obtain the auto-generated primary key, then add that as 
     the value of the
     <var class="varname"><var class="varname">co_id</var></var>
     column when inserting the department row.
    </p></div>
    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">require_once&nbsp;</span><span style="color: #DD0000">'SDO/DAS/Relational.php'</span><span style="color: #007700">;<br />require_once&nbsp;</span><span style="color: #DD0000">'company_metadata.inc.php'</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/*************************************************************************************<br />*&nbsp;Empty&nbsp;out&nbsp;the&nbsp;two&nbsp;tables<br />*************************************************************************************/<br /></span><span style="color: #0000BB">$dbh&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">PDO</span><span style="color: #007700">(</span><span style="color: #0000BB">PDO_DSN</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_USER</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_PASSWORD</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$pdo_stmt&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">prepare</span><span style="color: #007700">(</span><span style="color: #DD0000">'DELETE&nbsp;FROM&nbsp;COMPANY;'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$rows_affected&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$pdo_stmt</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">execute</span><span style="color: #007700">();<br /></span><span style="color: #0000BB">$pdo_stmt&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">prepare</span><span style="color: #007700">(</span><span style="color: #DD0000">'DELETE&nbsp;FROM&nbsp;DEPARTMENT;'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$rows_affected&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$pdo_stmt</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">execute</span><span style="color: #007700">();<br /><br /></span><span style="color: #FF8000">/**************************************************************<br />*&nbsp;Create&nbsp;a&nbsp;company&nbsp;with&nbsp;name&nbsp;Acme&nbsp;and&nbsp;one&nbsp;department,&nbsp;the&nbsp;Shoe&nbsp;department<br />***************************************************************/<br /></span><span style="color: #0000BB">$dbh&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">PDO</span><span style="color: #007700">(</span><span style="color: #0000BB">PDO_DSN</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_USER</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_PASSWORD</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$das&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">SDO_DAS_Relational&nbsp;</span><span style="color: #007700">(</span><span style="color: #0000BB">$database_metadata</span><span style="color: #007700">,</span><span style="color: #DD0000">'company'</span><span style="color: #007700">,</span><span style="color: #0000BB">$SDO_containment_metadata</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$root&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$das&nbsp;</span><span style="color: #007700">-&gt;&nbsp;</span><span style="color: #0000BB">createRootDataObject</span><span style="color: #007700">();<br /><br /></span><span style="color: #0000BB">$acme&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$root&nbsp;</span><span style="color: #007700">-&gt;&nbsp;</span><span style="color: #0000BB">createDataObject</span><span style="color: #007700">(</span><span style="color: #DD0000">'company'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$acme&nbsp;</span><span style="color: #007700">-&gt;&nbsp;</span><span style="color: #0000BB">name&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">"Acme"</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$shoe&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$acme</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">createDataObject</span><span style="color: #007700">(</span><span style="color: #DD0000">'department'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$shoe</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">name&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'Shoe'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$das&nbsp;</span><span style="color: #007700">-&gt;&nbsp;</span><span style="color: #0000BB">applyChanges</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$root</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>

  <p class="para">
   <div class="example" id="example-5353">
    <p><strong>Example #2 One company, one department - Retrieve and Update</strong></p>

    <div class="example-contents"><p>
     In this case the SQL query passed to
     <span class="function"><strong>executeQuery()</strong></span>
     performs an inner join to join the data from the company 
     and department tables. Primary keys for both the company and 
     department tables must be included in the query. The result set 
     is re-normalised to form a normalised data graph. Note that a 
     column specifier is passed as the third argument to the 
     <span class="function"><strong>executeQuery()</strong></span>
     call enabling the Relational DAS to know which column is which in 
     the result set.
    </p></div>
    <div class="example-contents"><p>
     Note that the
     <var class="varname"><var class="varname">co_id</var></var>
     column although used in the query is not needed in the result set.
     In order to understand what the Relational DAS is doing when it builds 
     the data graph it may be helpful to visualise what the result set 
     looks like. Although the data in the database is normalised, so that 
     multiple department rows can point through their foreign key to one 
     company row, the data in the result set is non-normalised: that is, 
     if there is one company and multiple departments, the values for the 
     company are repeated in each row. The Relational DAS has to reverse 
     this process and turn the result set back into a normalised data graph, 
     with just one company object.
    </p></div>
    <div class="example-contents"><p>
     In this example the Relational DAS will examine the result set and 
     column specifier, find data for both the company and department 
     tables, find primary keys for both, and interpret each row as 
     containing data for a department and its parent company. If it has 
     not seen data for that company before (it uses the primary key to 
     check) it creates a company object and then a department object 
     underneath it. If it has seen data for that company before and 
     has already created the company object it just creates the 
     department object underneath.
    </p></div>

    <div class="example-contents"><p>
     In this way the Relational DAS can retrieve and renormalise data 
     for multiple companies and multiple departments underneath them.
    </p></div>

    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">require_once&nbsp;</span><span style="color: #DD0000">'SDO/DAS/Relational.php'</span><span style="color: #007700">;<br />require_once&nbsp;</span><span style="color: #DD0000">'company_metadata.inc.php'</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/**************************************************************<br />*&nbsp;Retrieve&nbsp;the&nbsp;company&nbsp;and&nbsp;Shoe&nbsp;department,&nbsp;then&nbsp;delete&nbsp;Shoe&nbsp;and&nbsp;add&nbsp;IT<br />***************************************************************/<br /></span><span style="color: #0000BB">$dbh&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">PDO</span><span style="color: #007700">(</span><span style="color: #0000BB">PDO_DSN</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_USER</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_PASSWORD</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$das&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">SDO_DAS_Relational&nbsp;</span><span style="color: #007700">(</span><span style="color: #0000BB">$database_metadata</span><span style="color: #007700">,</span><span style="color: #DD0000">'company'</span><span style="color: #007700">,</span><span style="color: #0000BB">$SDO_containment_metadata</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$root&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$das</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">executeQuery</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">,<br /></span><span style="color: #DD0000">'select&nbsp;c.id,&nbsp;c.name,&nbsp;d.id,&nbsp;d.name&nbsp;from&nbsp;company&nbsp;c,&nbsp;department&nbsp;d&nbsp;where&nbsp;d.co_id&nbsp;=&nbsp;c.id'</span><span style="color: #007700">,<br />array(</span><span style="color: #DD0000">'company.id'</span><span style="color: #007700">,</span><span style="color: #DD0000">'company.name'</span><span style="color: #007700">,</span><span style="color: #DD0000">'department.id'</span><span style="color: #007700">,</span><span style="color: #DD0000">'department.name'</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">$acme&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$root</span><span style="color: #007700">[</span><span style="color: #DD0000">'company'</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">];&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;get&nbsp;the&nbsp;first&nbsp;company&nbsp;-&nbsp;will&nbsp;be&nbsp;'Acme'<br /></span><span style="color: #0000BB">$shoe&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$acme</span><span style="color: #007700">[</span><span style="color: #DD0000">'department'</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">];&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;&nbsp;</span><span style="color: #FF8000">//&nbsp;get&nbsp;the&nbsp;first&nbsp;department&nbsp;underneath&nbsp;-&nbsp;will&nbsp;be&nbsp;'Shoe'<br /><br /></span><span style="color: #007700">unset(</span><span style="color: #0000BB">$acme</span><span style="color: #007700">[</span><span style="color: #DD0000">'department'</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">]);<br /><br /></span><span style="color: #0000BB">$it&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$acme</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">createDataObject</span><span style="color: #007700">(</span><span style="color: #DD0000">'department'</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$it</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">name&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #DD0000">'IT'</span><span style="color: #007700">;<br /><br /></span><span style="color: #0000BB">$das&nbsp;</span><span style="color: #007700">-&gt;&nbsp;</span><span style="color: #0000BB">applyChanges</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$root</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>

  <p class="para">
   <div class="example" id="example-5354">
    <p><strong>Example #3 One company, two departments - Retrieve and Delete</strong></p>
    <div class="example-contents"><p>
     In this example the company and department are retrieved and 
     then deleted. It is not necessary to delete them individually 
     (although that would be possible) - deleting the company object 
     from the data graph also deletes any departments underneath it.
    </p></div>
    <div class="example-contents"><p>
     Note the way that the company object is actually deleted using the 
     PHP unset call. The unset has to be performed on the containing 
     property which in this case is 
     the company property on the special 
     root object. You must use:
     <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">unset(</span><span style="color: #0000BB">$root</span><span style="color: #007700">[</span><span style="color: #DD0000">'company'</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">]);<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
     </div>

     and not:
     <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">unset(</span><span style="color: #0000BB">$acme</span><span style="color: #007700">);&nbsp;</span><span style="color: #FF8000">//WRONG<br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
     </div>

     Simply unsetting
     <var class="varname"><var class="varname">$acme</var></var>
     would destroy the variable but leave the data in the data 
     graph untouched.
    </p></div>

    <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000">
<span style="color: #0000BB">&lt;?php<br /></span><span style="color: #007700">require_once&nbsp;</span><span style="color: #DD0000">'SDO/DAS/Relational.php'</span><span style="color: #007700">;<br />require_once&nbsp;</span><span style="color: #DD0000">'company_metadata.inc.php'</span><span style="color: #007700">;<br /><br /></span><span style="color: #FF8000">/**************************************************************<br />*&nbsp;Retrieve&nbsp;the&nbsp;company&nbsp;and&nbsp;IT&nbsp;department,&nbsp;then&nbsp;delete&nbsp;the&nbsp;whole&nbsp;company<br />***************************************************************/<br /></span><span style="color: #0000BB">$dbh&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">PDO</span><span style="color: #007700">(</span><span style="color: #0000BB">PDO_DSN</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_USER</span><span style="color: #007700">,</span><span style="color: #0000BB">DATABASE_PASSWORD</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">$das&nbsp;</span><span style="color: #007700">=&nbsp;new&nbsp;</span><span style="color: #0000BB">SDO_DAS_Relational&nbsp;</span><span style="color: #007700">(</span><span style="color: #0000BB">$database_metadata</span><span style="color: #007700">,</span><span style="color: #DD0000">'company'</span><span style="color: #007700">,</span><span style="color: #0000BB">$SDO_containment_metadata</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">$root&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$das</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">executeQuery</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">,<br /></span><span style="color: #DD0000">'select&nbsp;c.id,&nbsp;c.name,&nbsp;d.id,&nbsp;d.name&nbsp;from&nbsp;company&nbsp;c,&nbsp;department&nbsp;d&nbsp;where&nbsp;d.co_id&nbsp;=&nbsp;c.id'</span><span style="color: #007700">,<br />array(</span><span style="color: #DD0000">'company.id'</span><span style="color: #007700">,</span><span style="color: #DD0000">'company.name'</span><span style="color: #007700">,</span><span style="color: #DD0000">'department.id'</span><span style="color: #007700">,</span><span style="color: #DD0000">'department.name'</span><span style="color: #007700">));<br /><br /></span><span style="color: #0000BB">$acme&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$root</span><span style="color: #007700">[</span><span style="color: #DD0000">'company'</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">];<br /></span><span style="color: #0000BB">$it&nbsp;</span><span style="color: #007700">=&nbsp;</span><span style="color: #0000BB">$acme</span><span style="color: #007700">[</span><span style="color: #DD0000">'department'</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">];<br /><br />unset(</span><span style="color: #0000BB">$root</span><span style="color: #007700">[</span><span style="color: #DD0000">'company'</span><span style="color: #007700">][</span><span style="color: #0000BB">0</span><span style="color: #007700">]);<br /><br /></span><span style="color: #0000BB">$das&nbsp;</span><span style="color: #007700">-&gt;&nbsp;</span><span style="color: #0000BB">applyChanges</span><span style="color: #007700">(</span><span style="color: #0000BB">$dbh</span><span style="color: #007700">,&nbsp;</span><span style="color: #0000BB">$root</span><span style="color: #007700">);<br /><br /></span><span style="color: #0000BB">?&gt;</span>
</span>
</code></div>
    </div>

   </div>
  </p>
 </div><hr /><div class="manualnavbar" style="text-align: center;">
 <div class="prev" style="text-align: left; float: left;"><a href="sdodasrel.examples.one-table.html">One-table examples</a></div>
 <div class="next" style="text-align: right; float: right;"><a href="sdodasrel.examples.three-table.html">Three-table example</a></div>
 <div class="up"><a href="sdodasrel.examples.html">范例</a></div>
 <div class="home"><a href="index.html">PHP Manual</a></div>
</div></body></html>
